Vertically adjustable table



Dec. 8, 1959 2,916,340

S. C. JACKSON VERTICALLY ADJUSTABLE TABLE 3 Sheets-Sheet 1 Filed Dec. 19, 1957 INVENTOR F 5 M C. JACKSON ATTORNEY-S Dec. 8, 1959 s. c. JACKSON VERTICALLY ADJUSTABLE TABLE 3 Sheets-Sheet 3 Filed Dec. 19, 1957 SAM C. JAcKsdN mid, 01,

ATTORNEYS ited States Patent-O 2,916,340 I VERTICALLY ADJUSTABLE TABLE Sam C. Jackson, Winston-Salem, NC.

Application December 19, 1957, Serial No. 703,886

2 Claims. (Cl. 31139) This invention relates to an adjustable table which can be used with its top at a relatively high elevation to serve as a dining table or for other suitable purposes and, which can also be used with its top at a relatively low elevation so as to serve as a coffee table, a childs table, or the like.

It is known to provide a table with means to adjust the height of the top thereof relative to the surface upon which it stands. However, almost without exception, these prior art adjustable tables involve cumbersome, unsightly mechanical linkage systems which place the tables in the category of monstrosities unsuitable for use as fine furniture.

The means for adjusting the height of the table top invariably is exposed to view and spoils any attempt to create an aesthetically appealing piece of furniture. Moreover, the means for adjusting the table top is often comprised of a complicated assemblage of many operating parts, some of which must be manually adjusted each time it is desired to change the height of the table top.

It is a principal object of this'invention to provide a table with means for adjusting the top thereof between relatively high and low heights as desired, wherein the adjusting means is of simple construction and is hidden from view thereby offering no detraction from the aesthetic appeal of the table.

Another object of this invention is to provide a table with means for adjusting the top thereof between relatively high and low heights as desired, wherein the adjusting means takes the form of a pair of spaced lug elements mounted on an oscillatable shaft, the lug elements being movable into and out of operative position by lever arms connected to the ends of the shaft and forming abutments for the legs of the table when in operative position to maintain the legs in two different relative positions corresponding to the high and low heights of the table top, thereby obviating the necessity for manual adjustments whenever the height of the table is to be changed.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which- Figure 1 is a side elevation of the table adjusted to a height suitable for a dining table;

Figure 2 is an end elevation looking along the line 22 at the left-hand end of the table shown in Figure 1;

Figure 3 is a view similar to Figure 1, but showing the table legs adjusted to a lower position to provide a low table, such as a coffee table;

Figure 4 is an end view similar to Figure 2 looking at the left-hand end of the table shown in Figure 3 and taken along the line 44 in Figure 3;

Figure 5 is a longitudinal cross-sectional view taken along the line 55 in Figure 2;

Figure 6 is a transverse cross-sectional view taken along the line 6-6 in Figure 5 and showing the stop elements or lugs for the table legs in abutment position;

Figure 7 is a longitudinal cross-sectional view taken along the same lines as that shown in Figure 5, but show mtgflthe table legs adjusted to a position to provide alow ta e;

Figure 8 is a transverse sectional view similar to Figure 6 but showing the stop elements or lugs for the table legs in non-abutment position just prior to changing the height of the table;

Figure 9 is a longitudinal sectional view taken'along line 9-9in Figure 8;

Figure 10 is a bottom plan view, partially shown in sectifn, looking upward along the line 10--10 inFigure Referring more specifically to the drawings, the table is shown as having a top 10 which may have foldable leaf members 11 and 12 hingedly secured to the side edges thereof by hinges 13. The table top 10 also has side frame pieces 14, 15 fixed to the underside thereof and spaced inwardly from the foldable leaf members 11, 12. end pieces 16, 17 are provided on the underside of the table top 10 to define with the side frame pieces 14, 15 a rectangular frame 18 depending downwardly from the table top 10. The leaves 11 and 12 may be held in outwardly raised position or level with the table top 10 by means of supporting slides 20 and 21, each of which are mounted for sliding movement on the lower surface of the table top 10 between identical sets of spaced guide members 23, 24. In each set, a connecting web 25 extends between the guide members 23, 24 at their inner ends to retain the slides 20, 21 between their respective guide members 23, 24 allowing sliding movement of the slides 20, 21 relative to the members 23, 24 and 25. These supporting slides 20, 21 loosely penetrate suitable apertures formed in the side frame pieces 14, 15 to extend beneath the leaves 11, 12 respectively when it is desired to maintain the leaves level with the table top 10.

The side frame members 14 and 15 have elongated grooves 26 and 27 positioned intermediate the top and bottom edges thereof, respectively, and extending throughout the length of said side frame members in horizontal alinement with each other. It will be observed in Figure 9 that an elongated filler block or abutment 28 is secured in the central portion of at least one of the grooves 26, 27 to prevent the table legs from being moved too close together as will subsequently be described,

As most clearly shown in Figure 10, the supporting structure for the table top 10 includes rods 30 and 31 which extend between the grooves 26, 27 with their opposite ends respectively mounted within the confines of the grooves 26, 27 for sliding movement therealong. The rods 30, 31 extend between first and second pairs of table legs or supports 32, 33 and 34, 35 respectively, the upper end portions of which are suitably apertured to receive the rods 30, 31 in oscillatable relationship therewith. The first pair of legs 32, 33 receives rod 30, while the second pair of legs 34, 35 receives rod 31. The legs 32, 33 comprising the first pair of legs are maintained in special parallel relationship by suitable brace members 36 extending therebetween. Similarly, the legs 34, 35 comprising the second pair of legs are maintained in spaced parallel relationship by brace members 37. The first pair of legs 32, 33 crosses the second pair of legs 34,

, 35 at an intermediate point with respect to the opposite ends of the legs, legs 32 and 34 being pivotally connected at their point of crossing by a pivot pin 40 with the legs 33 and 35 being similarly pivotally connected to each other by a pivot pin 40 at their point of crossing. The lower ends of these legs are adapted to engage the floor in supporting the table in an upright position.

The rods 30 and 31 have disposed therebetween and afiixed thereto one or more suitable tension springs 45 Patented Dec. 8, 1959 3 (two such springs being shown, by way of example, in Figure which tend to pull the rods 30 and 31 and consequently the upper end portions of the first and second pairs of legs toward each other.

In Figure 7, the legs are shown in the position they would occupy when the table top 10 is at its lowermost position, while in Figure 5, the upper ends of the legs are in the position they would occupy when the table top 10 is in elevated position. The means for allowing the table top 10 to be adjusted in one or the other of these positions will now be described. Extending beneath the table top 10, there is an oscillatable shaft 46. The shaft 46 is centrally disposed with respect to the side pieces 14, 15, and extends longitudinally within the frame 18 above the rods 30, 31 and transversely with respect thereto. The shaft 46 penetrates the end pieces 16 and 17 of the frame 18 and is provided with a crank or lever arm 47 on each end thereof positioned outwardly of the respective end piece. The end of either lever arm 47 may be manually pulled downwardly through an arc of approximately 90 for a purpose to be subsequently described.

Lugs or stop elements 48, 49 in the form of cam plates are rigidly secured to the oscillatable shaft 46, one such element being mounted on the shaft adjacent each end piece 16, 17 within the frame 18. The lugs 48, 49 normally extend downwardly in a direction perpendicular to the axis of the shaft 46 to a point below the rods 30, 31' respectively. It will be noted that the lugs 48 and 49 have suitable slots 50 and 51, respectively, formed therein intermediate the ends thereof. The slots 50 and 51 are adapted to accommodate the rods 31 and 30, respectively, as indicated in Figure 7, when the table legs assume the position placing the table top 10 at its lowermost elevation. It is contemplated that the slots 50 and 51 could be eliminated, in which case the rods 31 and 30 would be adapted to be positioned in abutment with the outer ends of their respective lugs 48 and 49 when the table top 10 is at its lowermost elevation. I

As previously indicated, in order to prevent the pairs of table legs from being moved too close together when the table is to be assembled with its top 10 at its highest elevated position, the filler block 28 (shown in Figure 9) is suitably secured in the central portion of one of the grooves 26, 27 so that the corresponding ends of the rods 30 and 31 may be drawn by the springs 45 into abutment with the block 28 at opposite ends thereof. The filler block 28 therefore defines the inner limit of the movement of each rod 30, 31 within the grooves 26, 27, which is the position taken by each rod 30, 31 when the table top 10 is at its highest elevation.

It will be observed that the lug 48 has secured to an intermediate portion thereof a tension spring 55. The opposite end of the tension spring 55 is suitably secured to the underside of the table top 10 adjacent side frame piece 15. The tension spring 55, as shown in Figure 10, extends perpendicularly away from the lug 48 and the oscillatable shaft 46 to which the lug 48 is rigidly secured for a purpose to be subsequently described.

In describing the adjustable feature of the table, it will be assumed that the table is initially in the position shown in Figures 1 and 5, wherein the table top 10 is at its highest vertical elevation. When in this position, the corresponding ends of the slidable rods 30 and 31 abut the opposite ends of the filler block 28, being resiliently held thereagainst by the tension springs 45. The lugs 48 and 49 depend perpendicularly from the axis of the oscillatable shaft 46 at this time (see Figure 6), acting as the outer abutments for the rods 30 and 31 to retain the table top 10 at its highest elevation by locking the pairs of table legs in one position even though one were to press downwardly on the table top 10 with a force great enough to overcome the actionof the tension springs 45 tending to pull the rods 30 and 31 together.

Should it be desired to lower the table top 10 from the position shown in Figures 1 and 5, a person has only to grasp either lever arm 47 and pull it downwardly through an arc of approximately while at the same time pressing downward on the table top 10 with a pressure great enough to overcome the action of the tension springs 45 tending to pull the rods 30 and 31 together. Since the tension springs 45 preferably possess only a slight force therein, it is not a difficult matter to overcome this force, and accordingly, relatively little downward pressure on the table top 10 is required. When either lever arm 47 is pulled downwardly as described, the shaft 46 is caused to rotate, thus moving each of the lugs 48, 49 to a position where they can no longer abut rods 31, 30, respectively thereby releasing the pairs of table legs for movement relative to the table top. It will be observed in Figure 8 that a suitable stop means, such as a screw 56 secured to the underside of the table top 10, is provided to limit the pivotal movement of the lug 48 toward the underside of the table top 10. Either lever arm 47 may be pulled downwardly until the lug 48, which moves toward the table top 10 in response to such an operation, abuts the screw 56.

The downward pressure on the table top 10 forces the rods 30, 31 further apart against the pull of the tension springs 45 by allowing the ends of the rods 30, 31 to slide away from each other within the grooves 26, 27. Since the lugs 48, 49 have been moved to a position where they can no longer abut the rods 31, 30, respectively, the rods 30, 31 may be forced apart sufliciently to permit them to be received within the slots 50, 51 formed in the lugs 48, 49 when the lugs 48, 49 are restored to their locking position as will be subsequently described.

Upon releasing the lever arm 47, the tension spring 55 attached to the lug 48 and having been stretched by the pivotal movement of the lug 48 toward the table top 10 contracts to pull the lug 48 back to its original position. Accordingly, the shaft 46 to which the lug 48 is rigidly secured is caused to rotate in a direction opposite to that originally taken as the lug 48 returns to its original position thereby restoring lug 49 to its original position also. It is important to provide the screw 56 as a stop means to limit the movement of the lug 48 toward the underside of the table top 10 to prevent stretching of the tension spring 55 past its dead center which would preclude the spring 55 from contracting when the lever arm 47 is released. If such a condition were brought about, the lugs 48, 49 could not return to their locking position upon the release of the lever arm 47.

When the lugs 48, 49 have been returned to their locking position wherein they depend downwardly from the shaft 46 in a perpendicular direction with respect to the axis thereof, the rods 30, 31 having been forced further apart a sufficient distance are received within the slots 51, 50, respectively, as shown in Figure 7. This arrangement places the table top 10 at its lowermost vertical elevation since the supporting pairs of legs therefor are locked in position with their upper and lower end portions spaced relatively far apart which shortens the effective vertical height of the legs.

Should it be desired to raise the table top 10 from the position shown in Figures 3 and 7, either lever arm 47 is pulled downwardly as previously indicated to rotate the shaft 46 and thus pivot the lugs 48, 49. This pivotal movement of the lugs 48, 49 disengages the rods 31, 30 from the slots 50, 51 formed therein and permits the tension springs 45 to contract. The contraction of the tension springs 45 pulls the rods 30, 31 toward each other as their ends are caused to slide within the grooves 26, 27. The rods 30, 31 assume positions in which they abut opposite ends of the filler block 28, whereupon the lever arm 47 may be released to allow the tension spring 55 to return the lugs 48, 49 to their locking positions.

It will be seen that the table has again assumed the position shown in Figures 1 and 5, in which the top 10 is at its highest elevation. Ordinarily, when adjusting the table from low to high position, only the lever arm 47 need be pulled downwardly because the contracting action of the tension springs 45 is usually sufiicient to bring about the necessary adjustment of the table legs. Should there be no response after the lever arm 47 has been moved downwardly, a light upward pressure applied against the underside of the table top It) will be sutficient to bring about the contraction of the tension springs 45 and efiect the desired adjustment.

Although the invention has been described in connection with lug elements permitting only two height adjustments for the table, it is apparent that the lug elements could be formed with a number of slots therein to provide a plurality of height adjustments for the table.

Moreover, it is contemplated that the first and second pairs of legs may be attached to the table top in such a manner that they will be required to move in unison, either toward or away from each other, in which case only a single lug element for either pair of legs would be necessary to provide vertical adjustability for the table top.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A table having a horizontally disposed top, first and second pairs of legs pivotally connected to each other intermediate the ends thereof and having upper end portions movable transversely with respect to the ends of said top along its underside, tensioning means resiliently pulling the upper end portions of said first and second pairs of legs toward each other, means maintaining a minimum distance between the upper end portions of said first pair of legs and those of said second pair, means to lock the upper end portions of said first and second pairs of legs in supporting position for said top, wherein the upper end portions of said first pair of legs are spaced the minimum distance from the upper end portions of said second pair of legs, and means for releasing said locking means, whereby the upper end portions of said first and second pairs of legs may be moved outwardly with respect to each other to increase the space therebetween and said locking means may be restored to lock- 6 ing position thereby shortening the effective vertical height of said first and second pairs of legs.

2. In a vertically adjustable table having a table top, releasable means for maintaining said table top in any one of a plurality of vertical elevations, said means comprising first and second pairs of legs pivotally connected together, said first and second pairs of legs being mounted on the table top and supporting said table top in a horizontal plane, a first rod member extending between said first pair of legs, a second rod member extending between said second pair of legs, means slidably mounting the opposite ends of each rod member on the underside of said table top, an elongate abutment positioned between said rod members, tensioned resilient means secured to each of said rod members and extending therebetween to urge said rod members against opposite ends of said abutment when said table top is at its highest vertical elevation, a shaft mounted on the underside of said table top and extending transversely with respect to said rod members, a stop element rigidly secured to said shaft adjacent each end thereof, each of said stop elements extending downwardly from said shaft in a direction perpendicular with respect to the axis thereof when in operative position, said stop elements straddling said first and second rod members and in engagement therewith in a first position when said table top is at its highest vertical elevation, and means to rotate said shaft through an are thereby moving said stop elements away from engagement with said rod members whereby each of said rod members may be moved outwardly with respect to its corresponding stop member to thereby shorten the effective vertical height of said pairs of legs, and upon said stop members being restored to operative position, said stop members engaging said rod members in a second position to maintain said table top at a lesser vertical elevation.

References Cited in the file of this patent UNITED STATES PATENTS 631,556 Bushnell Aug. 22, 1899 1,881,047 Doman Oct. 4, 1932 1,994,364 King Mar. 12, 1935 2,560,821 Rieman et al. July 17, 1951 2,692,807 Cordola Oct. 26, 1954 2,788,252 Davis Apr. 9, 1957 2,829,936 Anderson Apr. 8, 1958 

